FRS2 has been found to regulate the differentiation of human pluripotent cardiovascular progenitors and cardiomyocytes [34], while the inhibition of PDE9A reduces cardiac hypertrophy through natriuretic peptide-dependent cGMP-PKG signal transduction [35], all of which may be related to the increased heart size of Tibetan pigs. Here, PDE9A is linked to cardiac hypertrophy.